This invention relates generally to sterilization apparatus and, more particularly, to vessels for holding liquid sterilizing agents in evaporative sterilizing procedures.
Methods for sterilizing instruments are known in which the instruments to be sterilized are placed on a closable chamber along with an open vessel containing liquid sterilizing agent. After closing the chamber, the temperature is raised to evaporate the sterilizing agent and sterilize the instruments.
A sterilizing method is disclosed in Finnish Application No. 874366 assigned to applicant's assignee, in which the instruments to be sterilized are situated within a closed sterilizing chamber which is then heated to a suitable temperature and into which peracetic acid is either previously provided or introduced. The peracetic acid evaporates under the effect of the raised temperature and acts as a sterilizing agent to sterilize the instruments. Apparatus used in the sterilization procedure described in Finnish Application No. 874366 comprises a sterilizing chamber in which a heater and a vessel for the sterilizing agent are provided. Peracetic acid, a strong oxidizing agent, is used as the sterilizing agent to sterilize the instruments. Since peracetic acid does not corrode stainless steel, and since most instruments today are made of stainless steel, the peracetic acid does not have a corroding effect during the sterilization of such stainless steel instruments.
More particularly, in accordance with the method disclosed in Finnish Application 874366, a fully or partially closed pressure-free chamber is heated to a temperature of about 40.degree. C. by means of a glow lamp, hot-water coil, or small electric resistor. Peracetic acid is placed in a shallow vessel, for example a dish, from which it is evaporated by the effect of the heat conducted through the bottom wall of the chamber. It is also known that sterilization takes placed most reliably in an atmosphere in which the moisture content is higher than in the ambient atmosphere. The objects to be sterilized are placed on shelves within the sterilization chamber, preferably at the end of a working day, whereupon the sterilization technique occurs overnight so that the instruments may be removed from the chamber the next morning.
When the sterilization procedure has been completed, the chamber is emptied in any suitable manner such, for example, as by means of a water aspirator, ventilation hose, or equivalent. The peracetic acid does not cause damage to the environment but decomposes into water, oxygen and vinegar. The vinegar smell, which is a characteristic of peracetic acid, rapidly disappears when the objects sterilized are metallic instruments. Evaporation is slower, however, in the case of softer instruments and therefore they may require ventilation for some time after sterilization.
This sterilization method, however, has the drawback that when the peracetic acid is placed into the sterilization chamber in the shallow dish from which it is to evaporate by heating, it tends to splash over the brim of the vessel. Since almost all modern instruments in use today that are sterilized are made of stainless steel, peracetic acid accidently splashed on such instruments does not cause corrosion. However, thus, the peracetic acid splashes on other objects or onto the floor, it can cause serious corrosion. However, it is difficult to avoid such splashing since the vessel in which it is carried must be a relatively shallow and dish-like in order to maximize evaporation. Therefore, the brim of the vessel defining the space in which the peracetic acid is carried should not be excessively high.